Vessel sealing instrument with electrical cutting mechanism

ABSTRACT

An end effector assembly for use with an instrument for sealing vessels and cutting vessels includes a pair of opposing first and second jaw members which are movable relative to one another from a first spaced apart position to a second position for grasping tissue therebetween. Each jaw member includes an electrically conductive tissue contacting surface connected to an electrosurgical energy source. At least one of the jaw members includes an electrically conductive cutting element disposed within an insulator defined in the jaw member. A rigid structural support is included which is configured to support the electrically conductive tissue sealing surface and includes at least one flow channel defined therein.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/894,354 filed on Aug. 21, 2007, entitled “VESSEL SEALING INSTRUMENTWITH ELECTRICAL CUTTING MECHANISM,” which is a continuation of U.S.patent application Ser. No. 11/418,876 filed on May 5, 2006, entitled“VESSEL SEALING INSTRUMENT WITH ELECTRICAL CUTTING MECHANISM,” now U.S.Pat. No. 7,270,644, which is a continuation-in-part of U.S. patentapplication Ser. No. 10/932,612 filed on Sep. 2, 2004, entitled “VESSELSEALING INSTRUMENT WITH ELECTRICAL CUTTING MECHANISM,” now U.S. Pat. No.7,276,068, which is a continuation-in-part of PCT Application Serial No.PCT/US03/28539 filed on Sep. 11, 2003, entitled “ELECTRODE ASSEMBLY FORSEALING AND CUTTING TISSUE AND METHOD FOR PERFORMING SAME,” which claimsthe benefit of and priority to U.S. Provisional Application Ser. No.60/416,064 filed on Oct. 4, 2002, entitled “ELECTRODE ASSEMBLY FORSEALING AND CUTTING TISSUE AND METHOD FOR PERFORMING SAME,” the contentsof each of which are incorporated by reference herein in their entirety.

BACKGROUND

The present disclosure relates to a forceps used for both endoscopic andopen surgical procedures that includes an electrode assembly that allowsa user to selectively seal and/or cut tissue. More particularly, thepresent disclosure relates to a forceps that includes a first set ofelectrically conductive surfaces that applies a unique combination ofmechanical clamping pressure and electrosurgical energy to effectivelyseal tissue and a second set of electrically conductive surfaces that isselectively energizable to sever tissue between sealed tissue areas.

TECHNICAL FIELD

Open or endoscopic electrosurgical forceps utilize both mechanicalclamping action and electrical energy to effect hemostasis. Theelectrode of each opposing jaw member is charged to a different electricpotential such that when the jaw members grasp tissue, electrical energycan be selectively transferred through the tissue. A surgeon can eithercauterize, coagulate/desiccate and/or simply reduce or slow bleeding, bycontrolling the intensity, frequency and duration of the electrosurgicalenergy applied between the electrodes and through the tissue.

Certain surgical procedures require more than simply cauterizing tissueand rely on the combination of clamping pressure, electrosurgical energyand gap distance to “seal” tissue, vessels and certain vascular bundles.More particularly, vessel sealing or tissue sealing is arecently-developed technology that utilizes a unique combination ofradiofrequency energy, clamping pressure and precise control of gapdistance (i.e., distance between opposing jaw members when closed abouttissue) to effectively seal or fuse tissue between two opposing jawmembers or sealing plates. Vessel or tissue sealing is more than“cauterization”, which involves the use of heat to destroy tissue (alsocalled “diathermy” or “electrodiathermy”). Vessel sealing is also morethan “coagulation”, which is the process of desiccating tissue whereinthe tissue cells are ruptured and dried. “Vessel sealing” is defined asthe process of liquefying the collagen, elastin and ground substances inthe tissue so that the tissue reforms into a fused mass withsignificantly-reduced demarcation between the opposing tissuestructures.

To effectively seal tissue or vessels, especially thick tissue and largevessels, two predominant mechanical parameters must be accuratelycontrolled: 1) the pressure applied to the vessel; and 2) the gapdistance between the conductive tissue contacting surfaces (electrodes).As can be appreciated, both of these parameters are affected by thethickness of the vessel or tissue being sealed. Accurate application ofpressure is important for several reasons: to oppose the walls of thevessel; to reduce the tissue impedance to a low enough value that allowsenough electrosurgical energy through the tissue; to overcome the forcesof expansion during tissue heating; and to contribute to the end tissuethickness, which is an indication of a good seal. It has been determinedthat a typical instrument gap is optimum between about 0.001 and about0.006 inches. Below this range, the seal may shred or tear and the jawsmay “short circuit” and not deliver the proper energy to the tissue.Above this range, thin or small tissue structures may not be properly oreffectively sealed.

With respect to smaller vessels, the pressure applied becomes lessrelevant and the gap distance between the electrically conductivesurfaces becomes more significant for effective sealing. In other words,the chances of the two electrically conductive surfaces touching duringactivation increases as the tissue thickness and the vessels becomesmaller.

Typically, and particularly with respect to endoscopic electrosurgicalprocedures, once a vessel is sealed, the surgeon has to remove thesealing instrument from the operative site, substitute a new instrumentthrough the cannula and accurately sever the vessel along the newlyformed tissue seal. This additional step may be both time consuming(particularly when sealing a significant number of vessels) and maycontribute to imprecise separation of the tissue along the sealing linedue to the misalignment or misplacement of the severing instrument alongthe center of the tissue seal.

SUMMARY

The present disclosure relates to an end effector assembly for use withan instrument for sealing and cutting vessels and/or tissue. An endeffector assembly for use with an instrument for sealing vessels andcutting vessels includes a pair of opposing first and second jaw memberswhich are movable relative to one another from a first spaced apartposition to a second position for grasping tissue therebetween. Each jawmember includes an electrically conductive tissue contacting surfaceconnected to an electrosurgical energy source. At least one of the jawmembers includes an electrically conductive cutting element disposedwithin an insulator defined in the jaw member. A rigid structuralsupport is included which is configured to support the electricallyconductive tissue sealing surface and includes at least one flow channeldefined therein.

In one embodiment of the present disclosure a layer of insulativematerial is included which is disposed between the electricallyconductive tissue sealing surface and the rigid structural support. Therigid structural support or structural backing may include perforations.The insulator may be located between the perforations of the structuralbacking.

In yet another embodiment of the present disclosure the electricallyconductive cutting element may include at least one mechanicallyinterfacing surface configured to mate with the insulative material toretain the electrically conductive cutting element within the insulator.

In one embodiment according to the present disclosure the electricallyconductive tissue sealing surfaces are photochemically etched or formedfrom a stamping process. At least one of the insulators may beconfigured to at least partially extend to a position which is at leastsubstantially flush with the cutting element.

A second electrically conductive cutting element may be provided whichis disposed within the insulator of the second jaw member. The secondelectrically conductive cutting element may be disposed in generallyopposing relation to the first electrically conductive cutting element.

In yet another embodiment of the present disclosure an end effectorassembly for use with an instrument for sealing and cutting vesselsand/or tissue is provided. The assembly includes a pair of opposingfirst and second jaw members at least one of which being movablerelative to the other from a first position wherein the jaw members aredisposed in spaced relation relative to one another to a second positionwherein the jaw members cooperate to grasp tissue therebetween. Each jawmember includes a pair of spaced apart, electrically conductive tissuesealing surfaces extending along a length thereof, each tissue sealingsurface being adapted to connect to a source of electrosurgical energysuch that the tissue sealing surfaces are capable of conductingelectrosurgical energy through tissue held therebetween to effect aseal. An insulator is disposed between each pair of electricallyconductive sealing surfaces. The first jaw member includes anelectrically conductive cutting element disposed within the insulator ofthe first jaw member, the electrically conductive cutting elementdisposed in general vertical registration to the insulator on the secondjaw member. The assembly includes at least one tissue tensioningmechanism configured to provide tension to tissue held between jawmembers.

In another embodiment of the present disclosure a slot defined withinthe second jaw member is included, the slot configured to receive theelectrically conductive cutting element and create tension upon tissue.

In yet another embodiment of the present disclosure the electricallyconductive tissue sealing surfaces are disposed in an angularrelationship relative to one another, the electrically conductivecutting element may be constructed of an expandable material (e.g., ashape memory alloy such as Nitinol) or may include a spring-like device.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1A is a right, perspective view of an endoscopic bipolar forcepshaving a housing, a shaft and a pair of jaw members affixed to a distalend thereof, the jaw members including an electrode assembly disposedtherebetween;

FIG. 1B is a left, perspective view of an open bipolar forceps showing apair of first and second shafts each having a jaw member affixed to adistal end thereof with an electrode assembly disposed therebetween;

FIG. 2 is an enlarged view of the area of detail of FIG. 1B

FIGS. 3A-3F are enlarged, schematic end views showing a variety ofdifferent electrode assemblies according to the present disclosure withelectrical potentials identified for electrical cutting;

FIG. 4A is an enlarged, schematic end view showing one electrodeassembly configuration with tissue disposed between the jaw members;

FIG. 4B is a schematic end view showing the area of detail of FIG. 4A;

FIGS. 4C-4J are enlarged, schematic end views showing variousconfigurations for an upper jaw member to promote electrical cutting;

FIG. 5 is a schematic end view showing an alternate configuration of anelectrode assembly according to the present disclosure with theelectrical potentials for both the sealing phase and the cutting phaseidentified;

FIGS. 6A-6D are enlarged, schematic end views showing alternateconfigurations of the electrode assembly according to the presentdisclosure with the electrical potentials for both the sealing mode andthe cutting mode identified;

FIGS. 7A-7E are enlarged, schematic end views showing variousconfigurations for the lower jaw member to promote electrical cutting;

FIGS. 8A-8D are enlarged, schematic end views showing alternateconfigurations of the electrode assembly according to the presentdisclosure;

FIGS. 8E-8F are enlarged, schematic end views showing alternateconfigurations of the electrode assembly according to the presentdisclosure;

FIGS. 9A-9B are enlarged views showing alternate configurations ofelectrodes having a curved jaw;

FIGS. 10A-10D are enlarged views showing alternate configurations ofelectrodes having a curved jaw; and

FIGS. 11A-11C are enlarged views showing alternate configurations ofelectrodes of the present disclosure.

DETAILED DESCRIPTION

For the purposes herein, vessel/tissue cutting or vessel/tissue divisionis believed to occur when heating of the vessel/tissue leads toexpansion of intracellular and/or extra-cellular fluid, which may beaccompanied by cellular vaporization, desiccation, fragmentation,collapse and/or shrinkage along a so-called “cut zone” in thevessel/tissue. By focusing the electrosurgical energy and heating in thecut zone, the cellular reactions are localized creating a fissure.Localization is achieved by regulating the vessel/tissue condition andenergy delivery, which may be controlled by utilizing one or more of thevarious geometrical electrode and insulator configurations describedherein. The cut process may also be controlled by utilizing a generatorand feedback algorithm (and one or more of the hereindescribedgeometrical configurations of the electrode and insulator assemblies),which increases the localization and maximizes the so-called “cuttingeffect”.

For example, the below described factors may contribute and/or enhancevessel/tissue division using electrosurgical energy. Each of the factorsdescribed below may be employed individually or in any combination toachieve a desired cutting effect. For the purposes herein the term “cuteffect” or “cutting effect” refers to the actual division of tissue byone or more of the electrical or electromechanical methods or mechanismsdescribed below. The term “cutting zone” or “cut zone” refers to theregion of vessel/tissue where cutting will take place. The term “cuttingprocess” refers to steps that are implemented before, during and/orafter vessel/tissue division that tend to influence the vessel/tissue aspart of achieving the cut effect.

For the purposes herein the terms “tissue” and “vessel” may be usedinterchangeably since it is believed that the present disclosure may beemployed to seal and cut tissue or seal and cut vessels utilizing thesame inventive principles described herein.

It is believed that the following factors either alone or incombination, play an important role in dividing tissue:

-   -   Localizing or focusing electrosurgical energy in the cut zone        during the cutting process while minimizing energy effects to        surrounding tissues;    -   Focusing the power density in the cut zone during the cutting        process;    -   Creating an area of increased temperature in the cut zone during        the cutting process (e.g., heating that occurs within the tissue        or heating the tissue directly with a heat source);    -   Pulsing the energy delivery to influence the tissue in or around        the cut zone. “Pulsing” involves as a combination of an “on”        time and “off” time during which the energy is applied and then        removed repeatedly at any number of intervals for any amount of        time. The pulse “on” and “off” time may vary between pulses. The        pulse “on” typically refers to a state of higher power delivery        and pulse “off” typically refers to a state of lower power        delivery;    -   Spiking the energy delivery creates a momentary condition of        high energy application with an intent to influence the tissue        in or around the cut zone during the cut process. The momentary        condition may be varied to create periods of high energy        application;    -   Conditioning the tissue before or during the cutting process to        create more favorable tissue conditions for cutting. This        includes tissue pre-heating before the cutting processes and        tissue rehydration during the cutting process;    -   Controlling the tissue volume in or around the cut zone to        create more favorable conditions for tissue cutting;    -   Controlling energy and power delivery to allow vaporization to        enhance and or contribute to the cutting process. For example,        controlling the energy delivery to vaporize both intracellular        and/or extracellular fluids and/or other cellular materials and        foreign fluids within the cut zone;    -   Fragmenting the tissue or cellular material during the cutting        process to enhance tissue division in the cut zone;    -   Melting or collapsing the tissue or cellular material during the        cutting process to enhance tissue division in the cut zone. For        example, melting the tissue to create internal stress within the        tissue to induce tissue tearing;    -   Controlling tissue temperature, arcing, power density and/or        current density during the cutting process to enhance tissue        division in the cut zone;    -   Applying various mechanical elements to the tissue, such as        pressure, tension and/or stress (either internally or        externally) to enhance the cutting process;    -   Utilizing various other tissue treatments before or during the        cutting process to enhance tissue cutting, e.g., tissue sealing,        cauterization and/or coagulation; and    -   Movement/motion of one or more electrically charged or        insulative members.

Many of the electrode assemblies described herein employ one or more ofthe above-identified factors for enhancing tissue division. For example,many of the electrode assemblies described herein utilize variousgeometrical configurations of electrodes, cutting elements, insulators,partially conductive materials and semiconductors to produce or enhancethe cutting effect. In addition, by controlling or regulating theelectrosurgical energy from the generator in any of the ways describedabove, tissue cutting may be initiated, enhanced or facilitated withinthe tissue cutting zone. For example, the geometrical configuration ofthe electrodes and insulators may be configured to produce a so-called“cut effect”, which may be directly related to the amount ofvaporization or fragmentation at a point in the tissue or the powerdensity, temperature density and/or mechanical stress applied to a pointin the tissue. The geometry of the electrodes may be configured suchthat the surface area ratios between the electrical poles focuselectrical energy at the tissue. Moreover, the geometricalconfigurations of the electrodes and insulators may be designed suchthat they act like electrical (or thermal) sinks or insulators toinfluence the heat effect within and around the tissue during thesealing or cutting processes.

Referring now to FIGS. 1A and 1B, FIG. 1A depicts a bipolar forceps 10for use in connection with endoscopic surgical procedures and FIG. 1Bdepicts an open forceps 100 contemplated for use in connection withtraditional open surgical procedures. For the purposes herein, either anendoscopic instrument or an open instrument may be utilized with theelectrode assembly described herein. Different electrical and mechanicalconnections and considerations may apply to each particular type ofinstrument; however, the novel aspects with respect to the electrodeassembly and its operating characteristics remain generally consistentwith respect to both the open or endoscopic designs.

FIG. 1A shows a bipolar forceps 10 for use with various endoscopicsurgical procedures and generally includes a housing 20, a handleassembly 30, a rotating assembly 80, a switch assembly 70 and anelectrode assembly 105 having opposing jaw members 110 and 120 thatmutually cooperate to grasp, seal and divide tubular vessels andvascular tissue. More particularly, forceps 10 includes a shaft 12 thathas a distal end 16 dimensioned to mechanically engage the electrodeassembly 105 and a proximal end 14 that mechanically engages the housing20. The shaft 12 may include one or more known mechanically engagingcomponents that are designed to securely receive and engage theelectrode assembly 105 such that the jaw members 110 and 120 arepivotable relative to one another to engage and grasp tissuetherebetween.

The proximal end 14 of shaft 12 mechanically engages the rotatingassembly 80 (not shown) to facilitate rotation of the electrode assembly105. In the drawings and in the descriptions that follow, the term“proximal”, as is traditional, will refer to the end of the forceps 10that is closer to the user, while the term “distal” will refer to theend that is further from the user. Details relating to the mechanicallycooperating components of the shaft 12 and the rotating assembly 80 aredescribed in commonly-owned U.S. patent application Ser. No. 10/460,926entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS ANDCANNULAS” filed on Jun. 13, 2003 the entire contents of which areincorporated by reference herein.

Handle assembly 30 includes a fixed handle 50 and a movable handle 40.Fixed handle 50 is integrally associated with housing 20 and handle 40is movable relative to fixed handle 50 to actuate the opposing jawmembers 110 and 120 of the electrode assembly 105 as explained in moredetail below. Movable handle 40 and switch assembly 70 are of unitaryconstruction and are operatively connected to the housing 20 and thefixed handle 50 during the assembly process. Housing 20 is constructedfrom two component halves 20 a and 20 b, which are assembled about theproximal end of shaft 12 during assembly. Switch assembly is configuredto selectively provide electrical energy to the electrode assembly 105.

As mentioned above, electrode assembly 105 is attached to the distal end16 of shaft 12 and includes the opposing jaw members 110 and 120.Movable handle 40 of handle assembly 30 imparts movement of the jawmembers 110 and 120 from an open position wherein the jaw members 110and 120 are disposed in spaced relation relative to one another, to aclamping or closed position wherein the jaw members 110 and 120cooperate to grasp tissue therebetween.

Referring now to FIG. 1B, an open forceps 100 includes a pair ofelongated shaft portions 112 a and 112 b each having a proximal end 114a and 114 b, respectively, and a distal end 116 a and 116 b,respectively. The forceps 100 includes jaw members 120 and 110 thatattach to distal ends 116 a and 116 b of shafts 112 a and 112 b,respectively. The jaw members 110 and 120 are connected about pivot pin119, which allows the jaw members 110 and 120 to pivot relative to oneanother from the first to second positions for treating tissue. Theelectrode assembly 105 is connected to opposing jaw members 110 and 120and may include electrical connections through or around the pivot pin119. Examples of various electrical connections to the jaw members areshown in commonly-owned U.S. patent application Ser. Nos. 10/474,170,10/116,824, 10/284,562 10/472,295, 10/116,944, 10/179,863 and10/369,894, the contents of all of which are hereby incorporated byreference herein.

Each shaft 112 a and 112 b includes a handle 117 a and 117 b disposed atthe proximal end 114 a and 114 b thereof that each define a finger hole118 a and 118 b, respectively, therethrough for receiving a finger ofthe user. As can be appreciated, finger holes 118 a and 118 b facilitatemovement of the shafts 112 a and 112 b relative to one another, which,in turn, pivot the jaw members 110 and 120 from the open positionwherein the jaw members 110 and 120 are disposed in spaced relationrelative to one another to the clamping or closed position wherein thejaw members 110 and 120 cooperate to grasp tissue therebetween. Aratchet 130 may be included for selectively locking the jaw members 110and 120 relative to one another at various positions during pivoting.

More particularly, the ratchet 130 includes a first mechanical interface130 a associated with shaft 112 a and a second mating mechanicalinterface associated with shaft 112 b. Each position associated with thecooperating ratchet interfaces 130 a and 130 b holds a specific, i.e.,constant, strain energy in the shaft members 112 a and 112 b, which, inturn, transmits a specific closing force to the jaw members 110 and 120.The ratchet 130 may include graduations or other visual markings thatenable the user to easily and quickly ascertain and control the amountof closure force desired between the jaw members 110 and 120.

As best seen in FIG. 1B, forceps 100 also includes an electricalinterface or plug 200 that connects the forceps 100 to a source ofelectrosurgical energy, e.g., an electrosurgical generator (notexplicitly shown). Plug 200 includes at least two prong members 202 aand 202 b that are dimensioned to mechanically and electrically connectthe forceps 100 to the electrosurgical generator 500 (See FIG. 1A). Anelectrical cable 210 extends from the plug 200 and securely connects thecable 210 to the forceps 100. Cable 210 is internally divided within theshaft 112 b to transmit electrosurgical energy through variouselectrical feed paths to the electrode assembly 105.

One of the shafts, e.g., 112 b, includes a proximal shaftconnector/flange 119 that is designed to connect the forceps 100 to asource of electrosurgical energy such as an electrosurgical generator500. More particularly, flange 119 mechanically secures electrosurgicalcable 210 to the forceps 100 such that the user may selectively applyelectrosurgical energy as needed.

As best shown in the schematic illustration of FIG. 2, the jaw members110 and 120 of both the endoscopic version of FIG. 1A and the openversion of FIG. 1B are generally symmetrical and include similarcomponent features that cooperate to permit facile rotation about pivot19, 119 to effect the grasping and sealing of tissue. Each jaw member110 and 120 includes an electrically conductive tissue contactingsurface 112 and 122, respectively, which cooperate to engage the tissueduring sealing and cutting. At least one of the jaw members, e.g., jawmember 120, includes a electrically energizable cutting element 127disposed therein, which is explained in detail below. Together, and asshown in the various figure drawings described hereafter, the electrodeassembly 105 includes the combination of the sealing electrodes 112 and122 and the cutting element(s) 127.

The various electrical connections of the electrode assembly 105 areconfigured to provide electrical continuity to the tissue contactingsurfaces 110 and 120 and the cutting element(s) 127 through theelectrode assembly 105. For example, cable lead 210 may be configured toinclude three different leads, namely, leads 207, 208 and 209, whichcarry different electrical potentials. The cable leads 207, 208 and 209are fed through shaft 112 b and connect to various electrical connectors(not shown) disposed within the proximal end of the jaw member 110,which ultimately connect to the electrically conductive sealing surfaces112 and 122 and cutting element(s) 127. As can be appreciated, theelectrical connections may be permanently soldered to the shaft 112 bduring the assembly process of a disposable instrument or,alternatively, selectively removable for use with a reposableinstrument. Commonly owned U.S. patent application Ser. Nos. 10/474,170,10/116,824 and 10/284,562 all disclose various types of electricalconnections that may be made to the jaw members 110 and 120 through theshaft 112 b the contents of all of which being incorporated by referenceherein. In addition and with respect to the types of electricalconnections which may be made to the jaw members 110 and 120 forendoscopic purposes, commonly-owned U.S. patent application Ser. Nos.10/472,295, 10/116,944, 10/179,863 and 10/369,894 all disclose othertypes of electrical connections which are hereby incorporated byreference herein in their entirety.

The various electrical connections from lead 210 are typicallydielectrically insulated from one another to allow selective andindependent activation of either the tissue contacting surfaces 112 and122 or the cutting element 127 as explained in more detail below.Alternatively, the electrode assembly 105 may include a single connectorthat includes an internal switch (not shown) to allow selective andindependent activation of the tissue contacting surfaces 112, 122 andthe cutting element 127. The leads 207, 208 and 209 (and/or conductivepathways) do not encumber the movement of the jaw members 110 and 120relative to one another during the manipulation and grasping of tissue.Likewise, the movement of the jaw members 110 and 120 do notunnecessarily strain the lead connections.

As best seen in FIGS. 2-3F, various electrical configurations of theelectrode assembly 105 are shown that are designed to effectively sealand cut tissue disposed between the sealing surfaces 112 and 122 and thecutting elements 127 of the opposing jaw members 110 and 120,respectively. More particularly, and with respect to FIGS. 2 and 3A, jawmembers 110 and 120 include conductive tissue contacting surfaces 112and 122, respectively, disposed along substantially the entirelongitudinal length thereof (e.g., extending substantially from theproximal to distal end of the respective jaw member 110 and 120). Tissuecontacting surfaces 112 and 122 may be attached to the jaw member 110,120 by stamping, by overmolding, by casting, by overmolding a casting,by coating a casting, by overmolding a stamped electrically conductivesealing plate and/or by overmolding a metal injection molded seal plateor in other suitable ways. All of these manufacturing techniques may beemployed to produce jaw member 110 and 120 having an electricallyconductive tissue contacting surface 112 and 122 disposed thereon forcontacting and treating tissue.

With respect to FIG. 3A, the jaw members 110 and 120 both include aninsulator or insulative material 113 and 123, respectively, disposedbetween each pair of electrically conductive sealing surfaces on eachjaw member 110 and 120, i.e., between pairs 112 a and 112 b and betweenpairs 122 a and 122 b. Each insulator 113 and 123 is generally centeredbetween its respective tissue contacting surface 112 a, 112 b and 122 a,122 b along substantially the entire length of the respective jaw member110 and 120 such that the two insulators 113 and 123 generally opposeone another.

One or both of the insulators 113, 123 may be made from a ceramicmaterial due to its hardness and inherent ability to withstand hightemperature fluctuations. Alternatively, one or both of the insulators113, 123 may be made from a material having a high Comparative TrackingIndex (CTI) having a value in the range of about 300 to about 600 volts.Examples of high CTI materials include nylons and syndiotacticpolystyrenes. Other suitable materials may also be utilized either aloneor in combination, e.g., Nylons, Syndiotactic-polystryrene (SPS),Polybutylene Terephthalate (PBT), Polycarbonate (PC), AcrylonitrileButadiene Styrene (ABS), Polyphthalamide (PPA), Polymide, PolyethyleneTerephthalate (PET), Polyamideimide (PAI), Acrylic (PMMA), Polystyrene(PS and HIPS), Polyether Sulfone (PES), Aliphatic Polyketone, Acetal(POM) Copolymer, Polyurethane (PU and TPU), Nylon withPolyphenylene-oxide dispersion and Acrylonitrile Styrene Acrylate.

At least one jaw member 110 and/or 120 includes an electricallyconductive cutting element 127 disposed substantially within or disposedon the insulator 113, 123. As described in detail below, the cuttingelement 127 (in many of the embodiments described hereinafter) plays adual role during the sealing and cutting processes, namely: 1) toprovide the necessary gap distance between conductive surfaces 112 a,112 b and 122 a, 122 b during the sealing process; and 2) toelectrically energize the tissue along the previously formed tissue sealto cut the tissue along the seal. With respect to FIG. 3A, the cuttingelements 127 a, 127 b are electrically conductive; however, one or bothof the cutting elements 127 a, 127 b may be made from an insulativematerial with a conductive coating disposed thereon or one (or both) ofthe cutting elements may be non-conductive (see, e.g., FIG. 4A). Thedistance between the cutting element(s) 127 a and the opposing cuttingelement 127 b (or the opposing return electrode in some cases) may bedisposed within the range of about 0.000 inches to about 0.040 inches tooptimize the cutting effect.

The general characteristics of the jaw members 110 and 120 and theelectrode assembly 105 will initially be described with respect to FIG.3A while the changes to the other envisioned embodiments disclosedherein will become apparent during the description of each individualembodiment. Moreover, all of the following figures show the variouselectrical configurations and polarities during the cutting phase only.During the so called “sealing phase”, the jaw members 110 and 120 areclosed about tissue and the cutting elements 127 and 127 b may form therequisite gap between the opposing sealing surfaces 112 a, 122 a and 112b, 122 b. During activation of the sealing phase, the cutting elements127 a and 127 b are not necessarily energized such that the majority ofthe current is concentrated between opposing sealing surfaces, 112 a and122 a and 112 b and 122 b, to effectively seal the tissue. Stop members1160 a and 1160 b may also be employed to regulate the gap distancebetween the sealing surfaces in lieu of the cutting elements 127 a and127 b. The stop members 1160 a and 1160 b may be disposed on the sealingsurfaces 1112 a, 1122 a and 1112 b, 1122 b (see FIG. 4E), adjacent thesealing surfaces 1112 a, 1122 a and 1112 b, 1122 b or on theinsulator(s) 1113, 1123.

The cutting elements 127 a and 127 b are configured to extend from theirrespective insulators 113 and 123, respectively, and extend beyond thetissue contacting surfaces 112 a, 112 b and 122 a and 122 b such thatthe cutting elements 127 a and 127 b act as stop members (i.e., createsa gap distance “G” (See FIG. 3A) between opposing conductive sealingsurfaces 112 a, 122 a and 112 b, 122 b), which as mentioned abovepromotes accurate, consistent and effective tissue sealing. As can beappreciated, the cutting elements 127 a and 127 b also prevent theopposing tissue contacting surfaces 112 a, 122 a and 112 b, 122 b fromtouching, which eliminates the chances of the forceps 10, 100 shortingduring the sealing process.

As mentioned above, two mechanical factors play an important role indetermining the resulting thickness of the sealed tissue andeffectiveness of a tissue seal, i.e., the pressure applied betweenopposing jaw members 110 and 120 and the gap distance “G” between theopposing tissue contacting surfaces 112 a, 122 a and 112 b, 122 b duringthe sealing process. With particular respect to vessels, the cuttingelement 127 (or cutting elements 127 a and 127 b) extends beyond thetissue contacting surfaces 112 a, 112 b and/or 122 a, 122 b to yield aconsistent and accurate gap distance “G” during sealing within the rangeof about 0.001 inches to about 0.006 inches and, more preferably, withinthe range of about 0.002 inches and about 0.003 inches. Other gap rangesmay be preferable with other tissue types, such as bowel or largevascular structures. As can be appreciated, when utilizing one cuttingelement (as with some of the disclosed embodiments herein), e.g., 127,the cutting element 127 would be configured to extend beyond the sealingsurfaces 112 a, 112 b and 122 a, 122 b to yield a gap distance withinthe above working range. When two opposing cutting elements areutilized, e.g., 127 a and 127 b, the combination of these cuttingelements 127 a and 127 b yield a gap distance within the above workingrange during the sealing process.

With respect to FIG. 3A, the conductive cutting elements 127 a and 127 bare oriented in opposing, vertical registration within respectiveinsulators 113 and 123 of jaw members 110 and 120. Cutting elements 127a and 127 b may be substantially dull so as to not inhibit the sealingprocess (e.g., premature cutting) during the sealing phase of theelectrosurgical activation. In other words, the surgeon is free tomanipulate, grasp and clamp the tissue for sealing purposes without thecutting elements 127 a and 127 b mechanically cutting into the tissue.Moreover, in this instance, tissue cutting can only be achieved througheither: 1) a combination of mechanically clamping the tissue between thecutting elements 127 a and 127 b and applying electrosurgical energyfrom the cutting elements 127 a and 127 b, through the tissue and to thereturn electrodes, i.e., the electrically conductive tissue contactingsurfaces 112 b and 122 b as shown in FIG. 3A; or 2) applyingelectrosurgical energy from the cutting elements 127 a and 127 b throughthe tissue and to the return tissue contacting surfaces 112 b and 122 b.

The geometrical configuration of the cutting elements 127 a and 127 bmay play an important role in determining the overall effectiveness ofthe tissue cut. For example, the power density and/or currentconcentration around the cutting elements 127 a and 127 b is based uponthe particular geometrical configuration of the cutting elements 127 aand 127 b and the cutting elements' 127 a and 127 b proximity to thereturn electrodes, i.e., tissue contacting surfaces 112 b and 122 b.Certain geometries of the cutting elements 127 a and 127 b may createhigher areas of power density than other geometries. Moreover, thespacing of the return electrodes 112 b and 122 b to these currentconcentrations affects the electrical fields through the tissue.Therefore, by configuring the cutting elements 127 a and 127 b and therespective insulators 113 and 123 within close proximity to one another,the electrical power density remains high, which is ideal for cuttingand the instrument will not short due to accidental contact betweenconductive surfaces. The relative size of the cutting elements 127 a and127 b and/or the size of the insulator 113 and 123 may be selectivelyaltered depending upon a particular or desired purpose to produce aparticular surgical effect.

In addition, the cutting element 127 a (and/or 127 b) may beindependently activated by the surgeon or automatically activated by theGenerator once sealing is complete. A safety algorithm may be employedto assure that an accurate and complete tissue seal is formed beforecutting. An audible or visual indicator (not shown) may be employed toassure the surgeon that an accurate seal has been formed and the surgeonmay be required to activate a trigger (or deactivate a safety) beforecutting. For example, a smart sensor or feedback algorithm may beemployed to determine seal quality prior to cutting. The smart sensor orfeedback loop may also be configured to automatically switchelectrosurgical energy to the cutting element 127 a (and/or 127 b) oncethe smart sensor determines that the tissue is properly sealed. Theelectrical configuration of the electrically conductive sealing surfaces112 a, 112 b and 122 a, 122 b may also be automatically or manuallyaltered during the sealing and cutting processes to effect accurate andconsistent tissue sealing and cutting.

Turning now to the embodiments of the electrode assembly 105, asdisclosed herein, which show the various polarities during the tissuecutting phase, FIG. 3A as mentioned above includes first and second jawmembers 110 and 120 having an electrode assembly 105 disposed thereon.More particularly, the electrode assembly 105 includes firstelectrically conductive sealing surfaces 112 a and 112 b each disposedin opposing registration with second electrically conductive sealingsurfaces 122 a and 122 b on jaw members 110 and 120, respectively.Insulator 113 electrically isolates sealing surfaces 112 a and 112 bfrom one another allowing selective independent activation of thesealing surfaces 112 a and 112 b. Insulator 123 separates sealingsurfaces 122 a and 122 b from one another in a similar manner therebyallowing selective activation of sealing surfaces 122 a and 122 b.

Each insulator 113 and 123 is set back a predetermined distance betweenthe sealing surfaces 112 a, 112 b and 122 a, 122 b to define a recess149 a, 149 b and 159 a, 159 b, respectively, which, as mentioned above,affects the overall power densities between the electrically activatedsurfaces during both the sealing and cutting phases. Cutting element 127a is disposed within and/or deposited on insulator 113 and extendsinwardly therefrom to extend beyond the sealing surfaces 112 a, 112 b bya predetermined distance. In the embodiments wherein only one cuttingelement, e.g., 127 a, is shown, the cutting element 127 a extends beyondthe sealing surfaces 112 a, 112 b and 122 a and 122 b to define theaforementioned gap range between the opposing sealing surfaces 112 a,122 a and 112 b and 122 b. When two (or more) cutting elements 127 a and127 b are employed (e.g., at least one disposed within each insulator113 and 123) the combination of the cutting elements 127 a and 127 byield the desired gap distance within the working gap range.

During sealing, the opposing sealing surfaces 112 a, 122 a and 112 b,122 b are activated to seal the tissue disposed therebetween to createtwo tissue seals on either side of the insulators 113 and 123. Duringthe cutting phase, the cutting elements 127 a and 127 b are energizedwith a first electrical potential “+” and the right opposing sealingsurfaces 112 b and 122 b are energized with a second electricalpotential “−”. This creates a concentrated electrical path between thepotentials “+” and “−” through the tissue to cut the tissue between thepreviously formed tissue seals. Once the tissue is cut, the jaw members110 and 120 are opened to release the two tissue halves.

FIG. 3B discloses another embodiment according to the present disclosurethat includes similar elements as described above with respect to FIG.3A, namely, sealing surfaces 312 a, 312 b and 322 a, 322 b, insulators313 and 323 and cutting elements 327 a and 327 b with the exception thatthe left side of each insulator 313 and 323 is extended beyond sealingsurfaces 312 a and 322 a to a position that is flush with the cuttingelements 327 a and 327 b. The right side of each insulator 313 and 323is set back from sealing surfaces 312 a and 312 b, respectively.Configuring the electrode assembly 305 in this fashion may reduce straycurrent concentrations between electrically conductive surfaces 312 a,312 b and 322 a, 322 b and cutting elements 327 a and 327 b especiallyduring the cutting phase.

FIG. 3C discloses yet another embodiment according to the presentdisclosure and includes similar elements as above, namely, sealingsurfaces 412 a, 412 b and 422 a, 422 b, insulators 413 and 423 andcutting elements 327 a and 327 b. With this particular embodiment,during the cutting phase, both sets of opposing sealing surfaces 412 a,422 a and 412 b, 422 b are energized with the second electricalpotential “−” and the cutting elements 427 a and 427 b are energized tothe first electrical potential “+”. It is believed that this electrodeassembly 405 may create concentrated electrical paths between thepotentials “+” and “−” through the tissue to cut the tissue between thepreviously formed tissue seals.

FIG. 3D shows an electrode assembly 505 configuration similar to FIG. 3Bwith a similar electrical configuration to the embodiment of FIG. 3C.The electrode assembly 505 includes and includes similar components asdescribed above, namely, sealing surfaces 512 a, 512 b and 522 a, 522 b,insulators 513 and 523 and cutting elements 527 a and 527 b. Theopposing sealing electrodes 512 a, 522 b and 512 a, 522 b are energizedto the second electrical potential “−” during the cutting phase, whichas described above is believed to enhance tissue cutting. Withparticular embodiments like FIGS. 3C and 3D, it may be easier tomanufacture the electrode assembly 505 such that all of the sealingsurfaces 512 a, 512 b and 522 a, 522 b are energized to the sameelectrical potential rather than employ complicated switching algorithmsand/or circuitry to energize only select sealing surfaces like FIGS. 3Aand 3B.

FIG. 3E shows yet another embodiment of the electrode assembly 605 thatincludes opposing sealing surfaces 612 a, 622 a and 612 b, 622 b,cutting element 627 and insulators 613 and 623. By this particularembodiment, the electrode assembly 605 only includes one cutting element627 disposed within insulator 613 for cutting tissue. The cuttingelement 627 is disposed opposite insulator 623, which provides a dualfunction during activation of the electrode assembly 605: 1) provides auniform gap between sealing surfaces 612 a, 622 a and 612 b, 622 bduring the sealing phase; and 2) prevents the electrode assembly 605from shorting during the sealing and cutting phases. During activation,the cutting element 627 is energized to a first potential “+” and theopposing sealing surfaces 612 a, 622 a and 612 b, 622 b are energized toa second electrical potential “−” which creates an area of high powerdensity between the two previously formed tissue seals and cuts thetissue.

FIG. 3F shows yet another alternate embodiment of the electrode assembly705 that includes similar elements as described above, namely, sealingsurfaces 712 a, 712 b and 722 a, 722 b, cutting elements 727 a and 727 band insulators 713 and 723. During activation, only three of the foursealing surfaces are energized to the second potential “−”, e.g.,sealing surfaces 712 a, 712 b and 722 b while the cutting elements 727 aand 727 b are energized to the first potential “+”.

FIGS. 4A and 4B shows yet another embodiment of the electrode assembly805 according to the present disclosure showing tissue disposed betweenthe two jaw members 810 and 820 prior to activation of the sealingsurfaces 812 a, 812 b and 822 a, 822 b. With this particular embodiment,the insulators 813 and 823 are configured to have opposing triangularlike cross sections, which essentially “pinch” the tissue between theinsulators 813 and 823 when tissue is grasped between jaw members 810and 820. During sealing, energy is applied to the tissue through theopposing sealing plates 812 a, 822 a and 812 b, 822 b to effect twotissue seals on either side of the insulators 813 and 823. During thecutting phase, sealing electrodes 812 a and 822 a are energized to afirst potential “+” and sealing plates 812 b and 822 b are energized tothe second electrical potential “−” such that energy flows in thedirection of the indicated arrow “A”. In other words, it is believedthat the pinching of the tissue tends to control or direct the energyconcentration to specific tissue areas to effect tissue cutting.

Turning now to FIGS. 4C-4J, various geometrical configurations for theupper jaw member 910 for the electrode assembly 905 which may beutilized with a symmetrical or asymmetrical lower jaw member (not shown)to effectively seal and subsequently cut tissue. Using the variousgeometries of the jaw members tends to “pinch” the tissue during sealingprior to separation, which may enhance the tissue cutting processespecially when the pinched tissue areas are subject to high powerdensities. For the purposes herein, the pinch may be described as thearea of smallest tissue volume anywhere between the active tissue poles.Typically, the pinched tissue area is associated with high pressure.Many of the below described jaw configurations illustrate the pinchconcept and are envisioned to utilize a variety of polarityconfigurations to enhance or facilitate cutting. For the purposes ofclarification, only the polarity associated with the cutting phase isdepicted on each figure.

Moreover, any combination of electrical potential as hereinbeforedescribed may be utilized with the various jaw members (and each jawmember's opposing jaw member) to effectively seal tissue during a firstelectrical phase and cut tissue during a subsequent electrical phase. Assuch, the illustrated jaw members are labeled with a first electricalpotential “+”; however, the lower jaw member inclusive of the sealingsurfaces and cutting elements (which may or may not be a mirror image ofthe upper jaw member) may be energized with any combination of first andsecond electrical potential(s) (or other electrical potentials) toeffectively seal and subsequently cut tissue disposed between the jawmembers.

FIG. 4C shows one particular upper jaw member 910 that includes asealing surface 912 having a U-shaped recess 921 defined therein forhousing insulator 913. A cutting element 927 is disposed withininsulator 913 and is dimensioned to extend beyond the sealing surface912. The cutting element 927 may be an electrode or may be made from apartially conductive material. FIG. 4D shows a jaw member 1010 thatforms part of an electrode assembly 1005 that includes two sealingsurfaces 1012 a and 1012 b with an insulator 1013 disposed therebetween.The insulator 1013 includes a cutting element 1027 disposed therein thatextends beyond the sealing surfaces 1012 a and 1012 b much like theembodiments described above with respect to FIGS. 3A-3F. Again, thecutting element 1027 may be an electrode or made from a semi-conductormaterial. However, and as mentioned above, a differentgeometrically-shaped jaw member may be disposed opposite jaw member 1010with different electrical potentials to produce a particular sealing andcutting effect.

FIGS. 4E-4J show various geometrical configurations of at least one jawmember that is configured to both seal tissue during a first sealingphase and cut tissue during a subsequent cutting phase. In eachinstance, the particular geometrical configuration of the insulator isdesigned to focus current into high areas of power density to produce acutting effect and/or reduce the likelihood of current straying toadjacent tissue, which may ultimately damage the adjacent tissuestructures.

For example, FIG. 4E shows a jaw member 1110 that may be utilized withthe electrode assembly 1105 which includes sealing surfaces 1112 a and1112 b that are separated by a partially conductive material 1113. Amirror-like jaw member 1120 is shown in opposition to jaw member 1110and includes similar elements, namely, sealing surfaces 1122 a and 1122b and partially conductive material 1123. In this particular embodiment,the partially conductive materials 1113 and 1123 are generally roundedto include and apexes 1151 a and 1151 b, respectively, which extendbeyond the sealing surfaces 1112 a, 1112 b and 1122 a, 1122 b. Thepartially conductive materials 1113 and 1123 are typically made from amaterial that have conductive properties that over time generate areasof high power density at the apexes 1151 a and 1151 b to cut tissuedisposed thereunder. A series of stop members 1160 a and 1160 may bedisposed on surfaces 1112 a and 1122 b and prevent the apexes 1151 a and1151 b from touching and shorting.

During the sealing phase (not shown) the partially conductive materials1113 and 1123 are not energized and will generally act more asinsulating materials since by its nature it is only semi-conductive andare not as conductive as sealing surfaces 1112 a, 1112 b and 1122 a,1122 b. In other words, the current may be supplied to the sealingplates 1112 a, 1112 b and 1122 a, 1122 b and not directly to thepartially conductive materials 1113 and 1123, thereby producing themajority of the electrical effect between the opposing sealing plates1112 a, 1122 a and 1112 b, 1122 b of the jaw members 1110 and 1120.During the cutting phase (as shown), an electrical potential is supplieddirectly to the partially conductive materials 1113 and 1123, which isbelieved will make them more conductive and which produce areas of highpower density in the vicinity of the apexes 1151 a and 1151 b to cut thetissue.

For example, partially conductive material 1113 is supplied with a firstpotential and partially conductive material 1123 is supplied with asecond potential to facilitate cutting. Jaw member 1120 may also beconfigured to include a different geometrical configuration from jawmember 1110 to produce a particular cutting effect. Moreover, aninsulator (not shown) may be disposed between one or both of thepartially conductive materials 1113 and 1123 and its respective sealingsurface to reduce electrical conduction or heat transfer between oracross these elements.

FIG. 4F shows a similar electrode assembly 1205 having sealing surfaces1212 a and 1212 b that are separated by a partially conductive material1213 and wherein the partially conductive material 1213 is generallyrounded but does not extend beyond the sealing surfaces 1212 a and 1212b. The partially conductive material 1213 may be made from a materialsuch as those identified above that produces an area of high powerdensity at the apex 1251 to cut tissue disposed thereunder during thecutting phase. Again, the opposite jaw member (not shown) may beconfigured as a mirror image of the jaw member 1210 or may include adifferent geometrical configuration.

FIG. 4G shows another geometric configuration of a jaw member 1310 thatincludes sealing surfaces 1312 a and 1312 b separated by a partiallyconductive material 1313 wherein the partially conductive material isset back between the sealing surface 1312 a and 1312 b to define arecess 1349 therein. FIG. 4H shows yet another geometric configurationof a jaw member 1410 which forms part of an electrode assembly 1405 andthat includes sealing surface 1412 and a partially conductive material1413. As can be appreciated this particular arrangement does not includea second sealing surface on the upper jaw member 1410 but instead thepartially conductive material 1413 includes a notch-like recess 1449defined therein that has a cutting tip 1451, which extends beyondsealing surface 1412. The cutting tip 1451 extends beyond the sealingsurface 1412 enough to both maintain the necessary gap distance duringthe sealing phase and to eventually facilitate tissue cutting during thecutting phase by producing an area of high power density at the tip1451. Again, the opposite jaw member (not shown) may be configured as amirror image of the jaw member 1410 or may include a differentgeometrical configuration.

FIG. 4I includes yet another geometric configuration of the upper jawmember 1510 that forms part of an electrode assembly 1505 and thatincludes sealing surfaces 1512 a and 1512 b that are separated by aninsulator 1513. The insulator 1513 includes a generallyrectilinear-shaped semi-conductive cutting element 1527 disposedtherein, which extends beyond the sealing surfaces 1512 a and 1512 b.During the cutting phase, the semi-conductive cutting element 1527 isenergized by a first potential “+” and the sealing plates 1512 a, 1512 bis energized to a second potential “−”. The insulator 1513 isolates thepotentials between the partially conductive material 1527 and thesealing surfaces 1512 a and 1512 b during activation.

FIG. 4J shows still yet another geometric configuration showing a jawmember 1610 for an electrode assembly 1605 that is similar to FIG. 4Cabove and includes a C-shaped sealing plate 1612 having a recess 1621defined therein for housing an insulator 1613. The insulator 1613includes a semi-conductive cutting element 1627 housed therein forcutting tissue. During the cutting phase, the semi-conductive cuttingelement 1627 is energized to a first potential “+” and the sealing plate1612 is energized to a second potential “−” to effect tissue cutting.Again, the lower or second jaw member (not shown) may include the samegeometric configuration to enhance the cutting process.

FIG. 5 shows a schematically-illustrated example of electrical circuitryfor an electrode assembly 1905, which may be utilized to initially sealtissue between the sealing plates and subsequently cut tissue once thetissue seal(s) are formed. More particularly, jaw member 1910 includesinsulative housing 1916 that is dimensioned to house conductive sealingplates 1912 a and 1912 b with an insulator or partially conductivematerial 1913 disposed therebetween. Insulator/partially conductivematerial 1913 includes a recess 1921 defined therein that is dimensionedto retain a generally triangularly-shaped cutting element 1927 andextends beyond sealing surfaces 1912 a and 1912 b. Jaw member 1920includes an outer insulative housing 1926 that is dimensioned to houseelectrically conductive sealing surface 1922. Sealing surface 1922includes a recess 1933 defined therein that generally compliments thecross sectional profile of cutting element 1927. The cutting element1927 is dimensioned slightly larger than the recess 1933 such that a gapis formed when the jaw members are closed about tissue, the gap beingwithin the above-identified working range.

During sealing (Vseal), the sealing plates 1912 a and 1912 b areenergized to a first potential “+₁” and sealing plate 1922 is energizedto a second potential “−”. The cutting element is not energized. Sincethe insulator or semi-conductor does not conduct energy as well as theconductive sealing plates 1912 a and 1912 b, the first potential is noteffectively or efficiently transferred to the cutting element 1927 andthe tissue is not necessarily heated or damaged during the sealingphase. During the sealing phase energy is transferred from the sealingplates 1912 a and 1912 b through the tissue and to the return electrode1922 (Vreturn). It is believed that even if some energy is effectivelytransferred to the cutting element 1927 during the sealing phase, itwill simply preheat or pre-treat the tissue prior to separation andshould not affect the cutting phase. During the sealing phase, thecutting element 1927 mainly acts as a stop member for creating andmaintaining a gap between the opposing sealing surfaces 1912 a, 1912 band 1922.

During the cutting phase (Vcut), a first potential “+₂” is supplied tothe cutting element 1927 and a second potential “−” is supplied to thesealing surface 1922. The electrical parameters (power, current,waveform, etc.) associated with this phase may be the same or differentthan the potentials used for the sealing phase. It is believed thatsimilar first and second potentials may be utilized since differentcomponents with varying geometries are being energized, which bythemselves may create different electrical effects. As can beappreciated, during the cutting phase energy is transferred from thecutting element 1927 through the tissue and to the return electrode 1922(Vreturn). It is believed that even if some energy is transferred to thesealing plates 1912 a and 1912 b during the cutting phase through theinsulator/semi-conductor 1913, it will not detrimentally effect thealready formed tissue seals. Moreover, it is believed that one or moresensors (not shown), computer algorithms and/or feedback controlsassociated with the generator or internally disposed within the forcepsmay be employed to prevent overheating of the tissue during the sealingand cutting phases.

FIGS. 6A-6D show additional embodiments of jaw members having variouselectrode assemblies that may be utilized for sealing and cutting tissuedisposed between the jaw members. For example, FIG. 6A shows a first orupper jaw member 2010 for use with an electrode assembly 2005 thatincludes an electrically conductive sealing surface 2012 having a recess2021 defined therein dimensioned to house an insulator 2013. Theinsulator also includes a notch 2049 disposed therein that partiallyhouses a generally rectilinearly-shaped cutting electrode 2027.Electrode 2027 is recessed or set back within notch 2049. Jaw member2020 includes an electrically conductive sealing surface 2022 that isdisposed in substantial vertical registration with opposing sealingsurface 2012. Sealing surface 2022 includes a generallyrectilinearly-shaped insulator 2023 that extends towards jaw member 2010and is configured to abut electrode 2027 when the jaw members 2010 and2020 are moved into the closed position about tissue. As can beappreciated, the insulator 2023 acts as a stop member and creates a gapdistance within the above working range during the sealing process. Inaddition, the two insulators 2013 and 2023 insulate the upper jaw member2010 during the cutting phase and generally direct the cutting currentfrom the cutting element 2027 in an intense fashion towards the returnelectrode 2022 (Vreturn) to effectively cut tissue.

FIG. 6B shows yet another embodiment of an electrode assembly 2105disposed on jaw members 2110 and 2120. More particularly, jaw members2110 and 2120 include electrically conductive sealing surfaces 2112 and2122, respectively, disposed in general vertical registration relativeto one another and that are configured to seal tissue during the sealingphase. Much like the embodiment described above with respect to FIG. 6A,jaw member 2110 includes a recess 2121 defined therein dimensioned tohouse an insulator 2113. Jaw member 2120 includes an electricallyconductive sealing surface 2122 that is disposed in substantial verticalregistration with opposing sealing surface 2112. Jaw member 2120includes an insulator 2123 disposed therein that is disposed oppositerecess 2121.

The insulator 2113 also includes a T-shaped cutting element 2127 housedtherein which defines two notches 2149 a and 2149 b on either side of aleg or extension 2127 a which extends towards jaw member 2120. Thecutting element 2127 may be made from a relatively low conductivematerial and includes an area of highly conductive material 2139disposed at the distal end of the leg 2127 a. The highly conductivematerial 2139 is disposed in vertical registration with the insulator2123 disposed in jaw member 2120. During activation of the cuttingphase, it is believed that the highly conductive material 2139 willfocus the cutting current in an intense fashion towards the returnelectrode 2122 (Vreturn) to cut the tissue disposed between jaw members2110 and 2120.

FIG. 6C shows yet another set of jaw members 2210 and 2220 with anelectrode assembly 2205 disposed thereon for sealing and cutting tissue.More particularly, jaw member 2210 includes an electrically conductivesealing surface 2212 having a recessed portion 2221 disposed therein forhousing an insulator 2213 which, in turn, houses a generally V-shapedcutting element 2227 therein. Jaw member 2220 includes an electricallyconductive sealing surface 2222 which opposes sealing surface 2212 onjaw member 2210. During the sealing phase, sealing surfaces 2212 and2222 conduct electrosurgical energy through tissue held therebetween toeffect a tissue seal. V-shaped cutting element 2227 acts as a stopmember during the sealing phase.

During the cutting phase, V-shaped cutting element 2227 pinches thetissue held between the jaw members 2210 and 2220 and when activateddirects electrosurgical energy through the tissue in an intense fashionaround insulator 2213 and towards sealing surface 2212. Jaw member 2220remains neutral during the cutting phase and is not believed tosignificantly alter the direction of the electrical path to adverselyeffect the cutting process.

FIG. 6D shows yet another embodiment of jaw members 2310 and 2320 havingan alternative electrode assembly 2305 for sealing and cutting tissue.More particularly, the electrode assembly 2305 is similar to theelectrode configuration of the embodiment described with respect to FIG.6C with the exception that the lower jaw member 2320 includes aninsulator 2323 disposed in vertical registration with the cuttingelement 2327 disposed within the recess 2321 of the upper jaw member2310. In this instance, the cutting element 2327 is dimensioned to bewider than the insulator 2323 such that the rear portions of theV-shaped cutting, element extend laterally beyond the insulator 2323when the jaw members 2310 and 2320 are disposed in the closed position.In other words the, cutting element 2327 includes an overhang portionwhich is disposed in opposing vertical registration with the returnelectrode 2322. The insulator 2313 disposed within the recess 2321 ofthe upper jaw member 2310 helps to direct the electrosurgical energytowards the return electrode 2322 during cutting and reduces straycurrents to adjacent tissue structures.

During the sealing phase, sealing surfaces 2312 and 2322 conductelectrosurgical energy through tissue held therebetween to effect twotissues seals on opposite sides of insulator 2313. V-shaped cuttingelement 2327 acts as a stop member during the sealing phase. During thecutting phase, jaw member 2310 is neutralized and cutting element 2327is energized such that electrosurgical energy is directed from thecutting element 2327 through tissue held between the jaw members 2310and 2320 and to the return electrode 2322 (Vreturn). It is believed thatthe V-shaped cutting element 2327 will direct energy to the returnelectrode 2322 in an intense fashion around insulator 2323 and towardssealing surface 2212 to effectively cut the tissue between the alreadyformed tissue seals.

FIGS. 7A-7D show various geometric configurations of cutting elementsand insulators for use with the electrode assemblies of forceps 10, 100according to the present disclosure. For example, FIG. 7A shows oneembodiment wherein one of the electrode assemblies 2405 includes jawmembers 2420 having first and second electrically conductive sealingsurfaces 2422 a and 2422 b which are of opposite electrical potentialsand which are separated by a trapeziodally-shaped insulator 2423 whichextends beyond each respective sealing surface 2422 a and 2422 b. As canbe appreciated the particular shape of the frustoconically-shapedinsulator 2423 forms two recessed portions 2459 a and 2459 b between thesealing surfaces 2422 a, 2422 b and the insulator 2423 which isenvisioned to both pinch the tissue between the insulator 2423 and theopposing surface (e.g., another insulator or conductive surface) andcontrol the electrosurgical energy during activation to facilitatecutting.

FIG. 7B shows another similar embodiment which includes afrustoconcically-shaped insulator 2523 which does not extend beyond thesealing surfaces 2522 a and 2522 b but is actually slightly set backfrom the sealing surfaces 2522 a and 2522 b. Again, the particular shapeof the trapezoidally-shaped insulator 2523 forms two recessed portions2559 a and 2559 b between the sealing surfaces 2522 a, 2522 b and theinsulator 2523 which is envisioned to control the electrosurgical energyduring activation to enhance the cutting process.

FIG. 7C shows another geometrical configuration of an electrode assembly2605 which includes one active electrically conductive surface 2622 aand one neutral electrically conductive surface 2622 b during thecutting phase. A cutting element 2627 is disposed between the twosurfaces 2622 a and 2622 b and is separated from the surfaces by aninsulator 2623 which is recessed between the two surfaces 2622 a and2622 b to form notches or set back areas 2659 a and 2659 b. The cuttingelement 2627 is designed with a smaller radius of curvature than theactive electrode 2622 a such that during the cutting phase,electrosurgical energy is intensified to create a sufficient powerdensity to effectively cut tissue proximate the cutting element 2627.

FIG. 7D shows another geometric configuration of an electrode assembly2705 similar to the embodiment shown in FIG. 7C above wherein theinsulator 2723 is configured to be generally flush with the surfaces2722 a and 2722 b. The cutting element 2727 is disposed within theinsulator 2723 and extends from both the insulator 2723 and the surfaces2722 a and 2722 b towards an opposing surface on the other jaw member(not shown). It is believed that the shape of the insulator 2723 willdirect intensified electrosurgical current between the cutting element2727 and the active conductive surface 2722 a.

FIG. 7E shows yet another electrode assembly 2805 having a jaw member2820 with a geometric configuration similar FIG. 7C above wherein theinsulator 2823 is recessed between the two sealing surfaces 2822 a and2822 b. A generally rounded cutting element 2827 is disposed within theinsulator 2823. The cutting element 2827 includes a larger radius ofcurvature than the radius of curvature of the active surface 2822 a suchthat during the cutting phase, electrosurgical energy is intensified toeffectively cut tissue proximate the cutting element 2827.

As can be appreciated, the various geometrical configurations andelectrical arrangements of the electrode assemblies allow the surgeon toinitially activate the two opposing electrically conductive tissuecontacting surfaces and seal the tissue and, subsequently, selectivelyand independently activate the cutting element and one or more tissuecontacting surfaces to cut the tissue utilizing the various shownelectrode assembly configurations. Hence, the tissue is initially sealedand thereafter cut without re-grasping the tissue.

However, the cutting element and one or more tissue contacting surfacesmay also be activated to simply cut tissue/vessels without initiallysealing. For example, the jaw members may be positioned about tissue andthe cutting element may be selectively activated to separate or simplycoagulate tissue. This type of alternative embodiment may beparticularly useful during certain endoscopic procedures wherein anelectrosurgical pencil is typically introduced to coagulate and/ordissect tissue during the operating procedure.

A switch 70 may be employed to allow the surgeon to selectively activateone or more tissue contacting surfaces or the cutting elementindependently of one another. As can be appreciated, this allows thesurgeon to initially seal tissue and then activate the cutting elementby simply turning the switch. Rocker switches, toggle switches, flipswitches, dials, etc. are types of switches which can be commonlyemployed to accomplish this purpose. The switch may also cooperate withthe smart sensor (or smart circuit, computer, feedback loop, etc.) whichautomatically triggers the switch to change between the “sealing” modeand the “cutting” mode upon the satisfaction of a particular parameter.For example, the smart sensor may include a feedback loop whichindicates when a tissue seal is complete based upon one or more of thefollowing parameters: tissue temperature, tissue impedance at the seal,change in impedance of the tissue over time and/or changes in the poweror current applied to the tissue over time. An audible or visualfeedback monitor may be employed to convey information to the surgeonregarding the overall seal quality or the completion of an effectivetissue seal. A separate lead may be connected between the smart sensorand the generator for visual and/or audible feedback purposes.

The generator 500 delivers energy to the tissue in a pulse-likewaveform. It has been determined that delivering the energy in pulsesincreases the amount of sealing energy which can be effectivelydelivered to the tissue and reduces unwanted tissue effects such ascharring. Moreover, the feedback loop of the smart sensor can beconfigured to automatically measure various tissue parameters duringsealing (i.e., tissue temperature, tissue impedance, current through thetissue) and automatically adjust the energy intensity and number ofpulses as needed to reduce various tissue effects such as charring andthermal spread.

It has also been determined that RF pulsing may be used to moreeffectively cut tissue. For example, an initial pulse from the cuttingelement through the tissue (or the tissue contacting surfaces throughthe tissue) may be delivered to provide feedback to the smart sensor forselection of the ideal number of subsequent pulses and subsequent pulseintensity to effectively and consistently cut the amount or type oftissue with minimal effect on the tissue seal. If the energy is notpulsed, the tissue may not initially cut but desiccate since tissueimpedance remains high during the initial stages of cutting. Byproviding the energy in short, high energy pulses, it has been foundthat the tissue is more likely to cut.

Alternatively, a switch may be configured to activate based upon adesired cutting parameter and/or after an effective seal is created orhas been verified. For example, after effectively sealing the tissue,the cutting element may be automatically activated based upon a desiredend tissue thickness at the seal.

As mentioned in many of the above embodiments, upon compression of thetissue, the cutting element acts as a stop member and creates a gap “G”between the opposing conductive tissue contacting surfaces. Particularlywith respect to vessel sealing, the gap distance is in the range ofabout 0.001 to about 0.006 inches. As mentioned above, controlling boththe gap distance “G” and clamping pressure between conductive surfacesare two important mechanical parameters which need to be properlycontrolled to assure a consistent and effective tissue seal. The surgeonactivates the generator to transmit electrosurgical energy to the tissuecontacting surfaces and through the tissue to affect a seal. As a resultof the unique combination of the clamping pressure, gap distance “G” andelectrosurgical energy, the tissue collagen melts into a fused mass withlimited demarcation between opposing vessel walls.

Once sealed, the surgeon activates the cutting element to cut thetissue. As mentioned above, the surgeon does not necessarily need tore-grasp the tissue to cut, i.e., the cutting element is alreadypositioned proximate the ideal, center cutting line of the seal. Duringthe cutting phase, highly concentrated electrosurgical energy travelsfrom the cutting element through the tissue to cut the tissue into twodistinct halves. As mentioned above, the number of pulses required toeffectively cut the tissue and the intensity of the cutting energy maybe determined by measuring the seal thickness and/or tissue impedanceand/or based upon an initial calibrating energy pulse which measuressimilar parameters. A smart sensor (not shown) or feedback loop may beemployed for this purpose.

As can be appreciated, the forceps may be configured to automaticallycut the tissue once sealed or the instrument may be configured to permitthe surgeon to selectively divide the tissue once sealed. Moreover, itis envisioned that an audible or visual indicator (not shown) may betriggered by a sensor (not shown) to alert the surgeon when an effectiveseal has been created. The sensor may, for example, determine if a sealis complete by measuring one of tissue impedance, tissue opaquenessand/or tissue temperature. Commonly-owned U.S. application Ser. No.10/427,832 which is hereby incorporated in its entirety by referenceherein describes several electrical systems which may be employed toprovide positive feedback to the surgeon to determine tissue parametersduring and after sealing and to determine the overall effectiveness ofthe tissue seal.

The electrosurgical intensity from each of the electrically conductivesurfaces and cutting elements may be selectively or automaticallycontrollable to assure consistent and accurate cutting along thecenterline of the tissue in view of the inherent variations in tissuetype and/or tissue thickness. Moreover, it is contemplated that theentire surgical process may be automatically controlled such that afterthe tissue is initially grasped the surgeon may simply activate theforceps to seal and subsequently cut tissue. In this instance, thegenerator may be configured to communicate with one or more sensors (notshown) to provide positive feedback to the generator during both thesealing and cutting processes to insure accurate and consistent sealingand division of tissue. Any suitable feedback mechanism may be employedfor this purpose.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the present disclosure. For example, cutting element may bedimensioned as a cutting wire which is selectively activatable by thesurgeon to divide the tissue after sealing. More particularly, a wire ismounted within the insulator between the jaw members and is selectivelyenergizable upon activation of the switch.

The forceps may be designed such that it is fully or partiallydisposable depending upon a particular purpose or to achieve aparticular result. For example, the electrode assembly may beselectively and releasably engageable with the distal end of the shaftand/or the proximal end of shaft may be selectively and releasablyengageable with the housing and the handle assembly. In either of thesetwo instances, the forceps would be considered “partially disposable” or“reposable”, i.e., a new or different electrode assembly (or electrodeassembly and shaft) selectively replaces the old electrode assembly asneeded.

The electrode assembly may be selectively detachable (i.e., reposable)from the shaft depending upon a particular purpose, e.g., specificforceps could be configured for different tissue types or thicknesses.Moreover, a reusable forceps could be sold as a kit having differentelectrodes assemblies for different tissue types. The surgeon simplyselects the appropriate electrode assembly for a particular tissue type.

The forceps may also include a mechanical or electrical lockoutmechanism which prevents the sealing surfaces and/or the cutting elementfrom being unintentionally activated when the jaw members are disposedin the open configuration.

Although the subject forceps and electrode assemblies have beendescribed with respect to preferred embodiments, it will be readilyapparent to those having ordinary skill in the art to which itappertains that changes and modifications may be made thereto withoutdeparting from the spirit or scope of the subject devices. For example,although the specification and drawing disclose that the electricallyconductive surfaces may be employed to initially seal tissue prior toelectrically cutting tissue in one of the many ways described herein,the electrically conductive surfaces may be configured and electricallydesigned to perform any known bipolar or monopolar function such aselectrocautery, hemostasis, and/or desiccation utilizing one or both jawmembers to treat the tissue. Moreover, the jaw members in theirpresently described and illustrated formation may be energized to simplycut tissue without initially sealing tissue which may prove beneficialduring particular surgical procedures. Moreover, the various geometriesof the jaw members, cutting elements, insulators and semi-conductivematerials and the various electrical configurations associated therewithmay be utilized for other surgical instrumentation depending upon aparticular purpose, e.g., cutting instruments, coagulation instruments,electrosurgical scissors, etc.

Various arrangements may be utilized in order to assist in the cuttingof tissue. One such arrangement involves placing the tissue under atensile force, which thereby eases the tissue separation. Tension, asdefined herein, includes but is not limited to motion, force, pressure,stress and/or strain that is initiated by externally applied energyand/or internally generated energy. This tension assisted tissuedivision may be accomplished in a number of ways including but notlimited to grasping features, expanding jaw features, shearing features,compressible features, expanding electrodes, pinch effect, movingmembers, moving instruments, internal or external stress or strain. Someof the possible energy types include, but are not limited to mechanical,ultrasonic, harmonic, thermal, laser and microwave. Some envisionedembodiments are discussed hereinbelow with reference to FIGS. 8A-F.

FIG. 8A shows yet another embodiment of jaw members 2910 and 2920 havingan alternative electrode assembly 2905 for sealing and cutting tissue.More particularly, the electrode assembly 2905 is similar to theelectrode configuration of the embodiment described with respect to FIG.6D with the exception that graspers 2981 are provided which assist inthe cutting of tissue by creating tension on the tissue. The graspers2981 hold the tissue and provide added stress in the cut zone to assistin tissue division. The graspers 2981 may be constructed of any numberof materials including ceramic, polymeric, etc. As the tissue is heatedit contracts or shrinks creating tension between the graspers 2981,which, in turn, stretches the tissue and allows for cleaner separationof tissue. It is envisioned that the graspers 2981 could be used inconjunction with any of the embodiments described herein.

FIG. 8B shows another embodiment of jaw members 3010 and 3020 having analternative electrode assembly 3005 for sealing and cutting tissue. Moreparticularly, the electrode assembly 3005 is similar to that shown inFIG. 8A however, an expandable cutting electrode 3083 or jaw feature isincluded in order to provide additional tension to the tissue. It isenvisioned for expandable cutting electrode 3083 to be constructed of ashape memory alloy (SMA) such as Nitinol. A Shape-Memory Alloy is ametal that, after being strained, at a certain temperature reverts backto its original shape. Different types of expandable and compressiblematerials may be used to produce tension on the tissue (e.g. siliconwith a shore A durometer).

FIG. 8C shows another embodiment wherein the jaw members 3110 and 3120have an alternative electrode assembly 3105 for sealing and cuttingtissue. More particularly, the electrode assembly 3105 is similar tothat shown in FIG. 8A, however, a slot 3185 defined in jaw member 3120is further included which may work with graspers (not shown) or theexpandable material 3083 mentioned above to create a tensile force uponthe tissue during grasping. This design utilizes a mechanical shearingeffect to create tension upon the tissue.

FIG. 8D shows yet another embodiment of jaw members 3210 and 3220 havingan alternative electrode assembly 3205 for sealing and cutting tissue.More particularly, the electrode assembly 3205 is similar to that shownin FIG. 8A, however a spring or spring-like device 3287 is connected tothe cut electrode 3227 and a slot 3285 is included to create tissuetension when grasped. Although slot 3285 is shown without an insulatoran insulator could be included adjacent slot 3285. Spring 3287 may beconstructed of an expandable material such as Nitinol or other knownshape-memory alloys. The use of graspers 2981, expandable materials 3083and other methods of moving the cut electrode 3227 within the cuttingarea are also envisioned. As mentioned hereinbefore, cut electrode 3227may take on a variety of suitable geometrical configurations including,but not limited to, square, triangular, rounded, spiral, etc.

FIGS. 8E and 8F show alternate embodiments of jaw members 3310 and 3320having an alternative electrode assembly 3305 for sealing and cuttingtissue. In FIG. 8E the tissue is subjected to tension upon jaw closure.More specifically, the jaw members 3310, 3320 and electrodes 3327 areplaced in an angular relationship with each other providing a tensioningeffect when the jaw members 3310, 3320 are closed. Different sizes andshapes for the electrodes 3327 are contemplated. The numerous geometriesand configurations of electrodes 3327 and jaw members 3310, 3320described herein may be utilized in accordance with this embodiment.

FIG. 8F shows jaw member 3420 having a tissue tensioning mechanism 3489disposed between electrodes 3427. As tissue shrinkage occurs the tissuecomes into contact with the tensioning mechanism 3489, furtherstretching the tissue and providing additional tension. As shown in FIG.8F, the tensioning mechanism 3489 may have a pointed or triangular tipwhich aides in tissue division. However, multiple geometricalconfigurations are possible. The tensioning mechanism 3489 could berounded, rectangular, square, spiral, frusto-conical, etc. In FIG. 8Fthe tensioning mechanism 3489 is shown on the lower jaw 3420, however,the mechanism may also be on the upper jaw 3410, lower jaw 3420, orboth. Moreover, tensioning mechanisms 3489 may be placed in differentand varying locations on jaws 3410, 3420.

The electrode assembly 3505 as shown in FIG. 9A may be formed in avariety of suitable ways. FIGS. 9A and 9B show electrodes formed byusing metal deposition/photochemical etching or stamping processes.Although, only one jaw member 3510 is shown in the figures, the opposingjaw member 3520 is envisioned to have a similar or complimentaryconfiguration. FIG. 9A shows a seal plate 3591 having an electricallyconductive tissue sealing surface 3593 and a cut electrode orelectrically conductive cutting element 3527. The seal plate 3591 may bephotochemically etched or stamped and then formed into its final shapeby stages in a progressive stamping die. The stamping die would raisethe cut electrode 3527 above the seal surface 3593. Multiple thinsupports 3595 may be utilized to hold the cut electrode 3527 in place,only to be subsequently lanced out after the molding step to ensureelectrical insulation. Seal plate 3591 may be backed by a rigidstructural support 3599 that may be perforated to allow overmoldedmaterial to flow therethrough. Seal plate 3591 may then be overmolded orbonded to the final jaw shape. Crimping terminals 3590 may be includedto hold the wires or electrical connections in electrical communicationwith the seal plates 3591. The electrical connections may also besoldered or welded.

FIG. 9B shows a cross-sectional view of the seal plate 3591 of FIG. 9A.Raised cut electrode 3527 is shown having an indentation 3593 fromchemical milling or other methods. This indentation 3593 is located onthe side of cut electrode 3527 and serves to hold electrode 3527 inplace once embedded in plastic or other insulating materials. Structuralbacking 3599 (which may be perforated to allow overmolded material toflow therethrough) is shown underneath seal plate 3591. Seal plate 3591is shown surrounded by an insulative overmolded structure 3597.

FIG. 10A shows an alternate embodiment of the seal plate 3791 of thepresent disclosure. In this embodiment a curved jaw shape is shownhaving a current path 3799 or bridge located at the distal end of theseal plate 3791. As shown above the seal plate 3791 may extend beyondthe supporting jaw member 3710 and the cut electrode 3727 may extendthrough the center of the jaw member 3710. The outer edges of the curvedjaw 3710 may be used for manipulating and sealing tissue.

FIG. 10B is similar to that shown in FIG. 9B showing a cross-sectionalview of the seal plate 3791 of FIG. 10A. FIG. 10B shows a flow channel3780 with perforations located beneath the cut electrode 3727. Anoptional insulation layer 3782 may be provided between seal plate 3791and rigid structural support or backing 3795. Rigid structural support3795 may contain perforations that allow insulative overmolded structure3797 to flow therethrough during the manufacturing process. Thisprovides additional support for the seal plate 3791. As mentionedhereinbefore, the electrically conductive tissue sealing surfaces may beformed using a variety of suitable techniques including, but not limitedto, photochemical etching and stamping processes.

FIG. 10C shows jaw member 3710 according to another embodiment of thepresent disclosure having bridge 3799. Bridge 3799 may protrude outwardfrom jaw 3710 to provide additional functions such as mechanicaldissection. Alternatively, bridge 3799 could be folded under and coveredby overmolded structure 3797. FIG. 10D shows jaw member 3710 in itsfinal bent shape.

FIG. 11A shows jaw member 3910 according to yet another embodiment ofthe present disclosure. Jaw member 3910 includes pivot point 3984located on the proximal end of jaw member 3910. Jaw member 3910 isconfigured to pivot about the pivot point 3984 and may be affixed with apin, bolt, screw, or alternative mechanism. Hole 3997 can be used toopen/close or otherwise move the jaw member. Jaw member 3910 may furtherinclude flow holes 3986 and seal plate 3991 or seal plate support 3795.An insulator similar to 3782 may be used and constructed of a number ofdifferent materials including, but not limited to, polymeric, ceramic orother materials.

FIG. 11B shows an example of structural backing 4095 which may be usedto support the jaw members. Structural backing 4095 may be perforated toallow the overmolded material to flow therethrough during manufacturingfor securing purposes. The backing 4095 may be straight or curved,depending upon the shape of the jaw member. The backing 4095 may also beformed by stamping, photo-etching, machining, etc.

FIG. 11C shows yet another embodiment of a jaw member 4110 according tothe present disclosure without the flow holes 3986 shown in FIG. 11A.However, in this embodiment jaw member 4110 further includes a cam slot4188 defined therein in addition to the pivot hole 4184 of FIG. 11A. Camslot 4188 is configured and dimensioned to regulate the movement of jawmember 4110 from the open to close positions.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

1. A method of manufacturing a jaw member for use with an instrument forsealing and/or cutting tissue, the method comprising: forming a sealingplate having an electrically conductive tissue sealing surface; formingan electrically conductive cutting element in the electricallyconductive tissue sealing surface; forming the sealing plate into afinal shape in a progressive stamping die; backing the sealing platewith a rigid structural support; and overmolding the sealing plate andthe rigid structural support with an overmold material.
 2. The methodaccording to claim 1, wherein the sealing plate is formed by at leastone of a photochemical etching process and a stamping process.
 3. Themethod according to claim 1, wherein the electrically conductive cuttingelement is formed by at least one of a metal deposition process, aphotochemical etching process, and a stamping process.
 4. The methodaccording to claim 1, wherein the sealing plate is formed into a finalshape by stages in the progressive stamping die.
 5. The method accordingto claim 4, wherein when the sealing plate is formed in the progressivestamping die, the electrically conductive cutting element is raisedabove the electrically conductive issue sealing surface.
 6. The methodaccording to claim 1, further including providing at least one supportto hold the electrically conductive cutting element in place, the methodfurther including removing the at least one support after theovermolding step.
 7. The method according to claim 1, wherein the rigidstructural support includes at least one perforation defined therein toallow the overmold material to flow therethrough.
 8. The methodaccording to claim 1, wherein the overmold material is an insulativematerial.
 9. The method according to claim 1, wherein at least one ofthe sealing plate and the electrically conductive cutting elementincludes a crimping terminal, the method further including electricallycoupling an electrical element with the crimping terminal.
 10. Themethod according to claim 9, further including attaching the electricalelement to the crimping terminal by at least one of soldering orwelding.
 11. The method according to claim 1, further including formingan indentation on the electrically conductive cutting element, theindentation configured to hold the electrically conductive cuttingelement in place in the electrically conductive tissue sealing surface.12. The method according to claim 11, wherein the indentation is formedby chemical milling.
 13. The method according to claim 1, furtherincluding providing an insulating layer between the rigid structuralsupport and the sealing plate.
 14. The method according to claim 1,wherein the sealing plate includes a bridge located at a distal endthereof.
 15. The method according to claim 1, wherein the overmoldmaterial is overmolded over the bridge.
 16. The method according toclaim 1, wherein the final shape is a curved shape.
 17. The methodaccording to claim 1, wherein the rigid structural support is formed byat least one of stamping, photo-etching and machining.